Humans have their dynamite; wind and water have time on their side; but animals, too, can reshape their landscape on a massive scale. None of these are the work of a lone gopher or even a single mighty elephant, but generations and generations of animals slowly chipping away.

Mima Mounds

Thousands of dirt mounds 8 feet tall and 30 feet wide dot the pimpled landscape of Mima Mounds Natural Area Preserve in Washington State. The origin of Mima (my-ma) mounds has long been a mystery, with theories involving Native Americans, earthquakes, and, for the conspiracy-minded, aliens. The answer, according to new research, might actually be gophers. But how do such small creatures create such big mounds? It probably takes 500 to 700 years.

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When it rains, gophers living underground push the soil up to keep from drowning. Geologist Manny Gabet constructed a computer model of this burrowing behavior, as well as the soil conditions of the area, and found that the Mima mounds could form after the cumulative burrowing of several hundred years. While his research isn't yet definitive—the problem with such gradual processes is that you can't exactly watch it happen—it might simply be that generations of gophers can move mounds, if not mountains.

Kitum Cave

Try a lick if you want to know why the walls of Kitum Cave in Kenya are so scratched and gouged. The cave walls are covered in salt, which attracts buffaloes, antelopes, leopards, and, most importantly here, elephants, in search of a high-sodium snack in the pitch black cave. For thousands of years, elephants have used their tusks to knock off chunks of the walls, carving out large sections of the cave. When modern humans first discovered the cave, they mistook the tusk marks for the picks of ancient Egyptians mining for gold or diamonds.

However, be careful where you lick, because Kitum Cave is also infamous for being a source of the deadly Marburg virus, similar to Ebola. Scientists now think the virus is spread by bats that also inhabit the cave.

World's Largest Beaver Dam

Incredibly, the largest beaver dam in the world was discovered from space. Jean Thie was perusing satellite photos on Google Earth for unrelated research on melting permafrost when he stumbled upon, so to speak, a gigantic structure on the southern edge of Canada's Wood Buffalo National Park. At nearly 3,000 feet long, the dam is twice the size of Hoover Dam. Generations of beavers have felled trees to build their home here, which is visible on NASA satellite imagery as early as 1990.

Despite its colossal size, park rangers at the Wood Buffalo National Park only learned of the beaver dam when they got a call from a BBC film crew, who saw the announcement on Thie's blog. The area in northern Canada is remote, and wetlands surrounding it are too boggy to land helicopters for a human visit. If not for satellites, beavers could have kept gnawing at trees, and we would have never known what a feat of engineering lies in a Canadian marsh.

America's Roads

Before cars, before railroads, before even humans, there were animals. North America was once crisscrossed with paths trod out by the hooves of buffalo and elk. As Earl Swift writes in his recent book The Big Roads:

America's principal overland routes were descended from prehistory—they'd started as game trails, had been commandeered by Native American hunting parties, and later were widened into wagon roads by white settlers. Over decades of use, they'd been cleared of stumps—at least the big ones—but much of their engineering remained the work of buffalo and elk.

In other words, over time these old animal routes became hunting trails, which became early routes west, which became wagon roads, which were later paved and graded by toll-road buildings, and, in many cases, these routes became a backbone for the modern U.S. interstate system, all building off the now forgotten "work of buffalo and elk."

Animals unlucky enough to wander into a five-lane highway today quickly become roadkill. But the imprint of creatures that walked across North America hundreds of years ago can, amazingly, still be seen in our maps.